<!doctype html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>阿里巴巴前端校招</title>
	<style>
		* {
			margin: 0;
			padding: 0;
		}

		html,body {
			height: 100%;
		}

		body {
			min-width: 405px;
		}

		.left {
		
			width: 20%;
			margin-left: -100%;
			background-color: #456;
		}

		/*p {
			width: 100%;
			height: 100%;
			overflow: auto;
		}*/

		.right {
			width: 30%;
			margin-left: -30%;
			background-color: #abc;
		}

		.main {
			width: 100%;
			background-color: #444;

		}

		.main,.left,.right {
			float: left;
			height: 200px;
		}

		.mainIn {
			margin-left: 20%;
			margin-right: 30%;
		}
	
	</style>
	<script>
</script>
</head>
<body>
	<div class="main">
	<div class="mainIn">中间</div>
		
	</div>
	<div class="left">
		左边
	</div>
	<div class="right">
		右边
	</div>
</body>
</html>